Variants of current-mirror circuits for reducing current imbalance in parallel LED strings

Current-mirror (CM) circuits have been basic circuit components in many analog and integrated circuit designs. Their current control properties make them attractive in current balancing applications. In this paper, a range of variants of CM circuits applicable to reducing current imbalance in parallel LED strings without using a separate auxiliary power supply are presented. The features including advantages and disadvantages are addressed and commented. Practical results of their applications in high-power LED systems with parallel strings are included and used to highlight their performance for comparison purposes.